1) I dislike the "rolling a 1 is always a fail" rule. Robbie knocked that one down pretty convincingly somewhere on the Fringe a while ago. Not everything has at best a 5/6 success rate.

2) I dislike any game system where special characters can't be killed with bog-standard infantry by weight in numbers (mid-90s Warhammer, I'm looking in your direction). Makes for really boring games with no tactical interest.

Finally, more of a fluff peeve than anything else: I dislike sci-fi/modern games where charging into close combat against a unit with guns (unless from the rear) is anything other than extremely costly to the charging unit. There's a reason cavalry units no longer won battles after the invention of the machinegun.

_________________Time is an illusion. What has happend will happen again, what has not come to pass will do so again and again forever. What is currently happening will affect the future with it's ripples in the ocean of eternity.

Part of the problem there is I-go-you-go turn sequence. I also find this irritating for wargames, and prefer games that mess with it a bit, e.g. Space Marine, or the time limit on the Marine player's turn in Space Hulk - now that is a good game! Incidentally, in both those games close combat specialists die in droves attempting to charge units with ranged weapons (unless you're really clever or spot a mistake in your opponent's deployment).

There are lots of bad rules out there, although I wouldn't say that I have an unthinking knee-jerk hatred for them. Even a badly executed rule might have potential to be done better or it might be needed for some other reason. The 40K assault rules are a great example of rules that are horribly unrealistic and unbalanced but the game needs them that way. As long as swarms of biting Tyranids and Orks with meat cleavers are supposed to be serious military threats to armies equipped with machine guns and assault rifles, the shooting and assault rules will have to be unrealistic.
(Well, technically, you could make them realistic but an Ork Boy would be worth about 2 points and a starting Ork army would require 300 miniatures so that a handful could still survive long enough to enter assault.)

In any case, I would say there are several categories of bad rules out there. Including, but not limited to, the following:

- Crude and clunky game mechanics. The "my entire army moves and fires before you can respond" turn sequence of 40K is a prime example. Even mediocre games moved beyond this system a long time ago.

- Rules that contradict the fluff. Often you have to sacrifice a bit of realism to make the game work. But if you can't be true to reality, at least be true to your own fictional world! Classic BattleTech had issues with this one early on... they made it extremely clear right from the beginning the 'Mechs were the ultimate and undisputed lords of the battlefield. Then they quickly published aerospace fighter rules that so totally owned 'Mechs that all ground forces would have been rendered obsolete. (The rules were eventually fixed.) Warhammer 40K has one famous example of this very same effect. The fluff is very consistent that Space Marines are awesomely superhuman and easily worth ten times their number in other troops. But the rules make them quite mediocre and these super rare and difficult to replace supermen die in droves every game.

- Rules that encourage/condone unrealistic/unfluffy gameplay. Basically, if the most effective tactics are unrealistic or unfluffy, there is a disconnect between the rules and what they are supposed to represent. Classic BattleTech long had a rule that made it more dangerous to take cover than it was to stand in the open. I've seen more than one greater daemon of Khorne hiding timidly behind a formation of moving Rhinos in order to advance up the field. The 3rd Edition Salamanders rules were supposed to make them shooty at close range but bad in assault. What they really did was make them good at long range shooting, so the best way to win with them was also completely unfluffy.

- Excessive randomness. A certain degree of randomness can make a game more exciting and challenging. But if luck has too big an effect tactics and planning become meaningless. 40K is better now than it was in the last couple of editions but the primitive turn sequence made the roll to see who goes first into a game-winning moment far too often. Did the Imperial Guard army get to go first? S8 AP3 pie plates vaporize half your squads while a wall of inaccurate but numerous lascannons punch holes in all your vehicles. Okay, your turn! (as you look at the pitiful smoking remains of your force.) Possibly the Speed Freaks or Kroot Mercenaries army lists were the ultimate examples of the "I go first = I win" army. Fortunately a lot of examples of bad randomness have been removed from more recent 40K rules (like the 3rd Edition "sudden death" deep strike rules that tended to vaporize your squads as often as it gave them an advantage).

_________________"Every man is guilty of all the good he did not do." - Voltaire
"It is to be expected that we will run out of fossil fuels before we run out of optimists, who are, along with fools and madmen, a renewable resource." - Dmitry Orlov

1.) not being able to run withing 8". whoever though this up HAD to be on crack. if played literally (which i have never seen) this rule completely kills the game.
so im on one side of a building and an enemy i cant see and cant hear is on the other side within 8" thus i cant run? give me a break.

2.) disarm destroying a weapon permanently. so i am meant to believe that every single piece of equipment in the underhive is so fragile that it cant survive being dropped on the ground? again, give me a break.
sadly, my group actually uses this rule, much to my continual annoyance and head against wall banging disbelief.

1) definite success. Yes, it may be right, it may be impossible to miss at that range, and dam it if a baneblade should vaporise stuff with ease, I want to be able to fail, prefrably with epic results for either player.

2) overly long after game sequences: Yes, Necromunda annoys me in that regard.

3) being against the Fluff: Yeah, this is completely right, in my mind I keep thinking that marines should be given a major buff and points boost and then be allowed to be an elite slot in Imperium forces with like... a max of 10% of the points going towards them.

4) Uber armies: yes, this is highly personal as much as a general complaint, but I have an irational hatred of any army which consists of ridiculously hard to kill opposition (marines, again a subject of hate) even at the basic troop level.

Though, to justify why I don't like them. It's not because their hard to kill (I once wiped marines off the table in 2 turns as tau at 750pts) it's that it's no fun to me. My group have a very literal belief that if it would be awesome then do it (resulting in half my gang tumbling down the stair case in a tide of water at one point to much chuckles as I fail six I checks). To me, facing an army where I get 9 hits and only 3 kills from those just isn't fun (again, baneblade, vaporise, those two words should stay in the same sentence at all time)

5) BALANCE!: Yays! My opponent is abusing the rules to get a really uber army! Seriously, everyone likes balance, we'd all love it to be completely and utterly fair, but people who whine about it to a collasol degree just make me want to howl. No, it's not fair, but if you were a better player, then probably, that little advantage they have would mean bugger all.

Magic has been a real sticking point in my group - mainly owing to some bad experiences they had with early WH demigod-wizards. I think WH magic is pretty good now though.

'The Omnipotence Question' - that is to say, can my troops react to something they don't know is there? This is a difficult one to get around unless you have maps and a GM.

Ammunition/fatigue - again this is a problem to keep track of in big battle games which is why I've never come across a ruleset which included it. Men get tired; they cannot charge round a field all day without affecting their performance.
For some reason games designers think that if you're not using firearms then you can't run out of ammo! I don't like it when archers/javelin men etc can blaze away the entire game.